﻿﻿using System;
using System.Data;
using System.IO;
using System.Text;
using System.Web;
using NPOI.HPSF;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;


public class ExcelHelper
{
    /// <summary>   
    /// DataTable导出到Excel文件   
    /// </summary>   
    /// <param name="dtSource">源DataTable</param>   
    /// <param name="strHeaderText">表头文本</param>   
    /// <param name="strFileName">保存位置</param>
    /// <param name="strSheetName">工作表名称</param>
    /// <Author>chenjh 2010-5-8 22:21:41</Author>   
    public static void Export(DataTable dtSource, string strHeaderText, string strFileName, string strSheetName, string[] oldColumnNames, string[] newColumnNames)
    {
        if (strSheetName == "")
        {
            strSheetName = "Sheet";
        }
        using (MemoryStream ms = Export(dtSource, strHeaderText, strSheetName, oldColumnNames, newColumnNames))
        {
            using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write))
            {
                byte[] data = ms.ToArray();
                fs.Write(data, 0, data.Length);
                fs.Flush();
            }
        }
    }

    /// <summary>   
    /// DataTable导出到Excel的MemoryStream   
    /// </summary>   
    /// <param name="dtSource">源DataTable</param>   
    /// <param name="strHeaderText">表头文本</param>   
    /// <param name="strSheetName">工作表名称</param>
    /// <Author>chenjh 2010-5-8 22:21:41</Author>   
    public static MemoryStream Export(DataTable dtSource, string strHeaderText, string strSheetName, string[] oldColumnNames, string[] newColumnNames)
    {
        if (oldColumnNames.Length != newColumnNames.Length)
        {
            return new MemoryStream();
        }
        HSSFWorkbook workbook = new HSSFWorkbook();
        //HSSFSheet sheet = workbook.CreateSheet();// workbook.CreateSheet();
        ISheet sheet = workbook.CreateSheet(strSheetName);

        #region 右击文件 属性信息
        {
            DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
            dsi.Company = "http://....../";
            workbook.DocumentSummaryInformation = dsi;

            SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
            if (HttpContext.Current.Session["realname"] != null)
            {
                si.Author = HttpContext.Current.Session["realname"].ToString();
            }
            else
            {
                if (HttpContext.Current.Session["username"] != null)
                {
                    si.Author = HttpContext.Current.Session["username"].ToString();
                }
            }                                       //填加xls文件作者信息   
            si.ApplicationName = "NPOI";            //填加xls文件创建程序信息   
            si.LastAuthor = "OA系统";           //填加xls文件最后保存者信息   
            si.Comments = "OA系统自动创建文件";      //填加xls文件作者信息   
            si.Title = strHeaderText;               //填加xls文件标题信息   
            si.Subject = strHeaderText;              //填加文件主题信息   
            si.CreateDateTime = DateTime.Now;
            workbook.SummaryInformation = si;
        }
        #endregion

        ICellStyle dateStyle = workbook.CreateCellStyle();
        IDataFormat format = workbook.CreateDataFormat();
        dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

        #region 取得列宽
        int[] arrColWidth = new int[oldColumnNames.Length];
        for (int i = 0; i < oldColumnNames.Length; i++)
        {
            arrColWidth[i] = Encoding.GetEncoding(936).GetBytes(newColumnNames[i]).Length;
        }
        /*
        foreach (DataColumn item in dtSource.Columns)
        {
            arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length;
        }
         * */

        for (int i = 0; i < dtSource.Rows.Count; i++)
        {
            for (int j = 0; j < oldColumnNames.Length; j++)
            {
                int intTemp = Encoding.GetEncoding(936).GetBytes(dtSource.Rows[i][oldColumnNames[j]].ToString()).Length;
                if (intTemp > arrColWidth[j])
                {
                    arrColWidth[j] = intTemp;
                }
            }
            /*
            for (int j = 0; j < dtSource.Columns.Count; j++)
            {
                int intTemp = Encoding.GetEncoding(936).GetBytes(dtSource.Rows[i][j].ToString()).Length;
                if (intTemp > arrColWidth[j])
                {
                    arrColWidth[j] = intTemp;
                }
            }
             * */
        }
        #endregion
        int rowIndex = 0;

        foreach (DataRow row in dtSource.Rows)
        {
            #region 新建表，填充表头，填充列头，样式
            if (rowIndex == 65535 || rowIndex == 0)
            {
                if (rowIndex != 0)
                {
                    sheet = workbook.CreateSheet(strSheetName + ((int)rowIndex / 65535).ToString());
                }

                #region 表头及样式
                {
                    IRow headerRow = sheet.CreateRow(0);
                    headerRow.HeightInPoints = 25;
                    headerRow.CreateCell(0).SetCellValue(strHeaderText);

                    ICellStyle headStyle = workbook.CreateCellStyle();
                    headStyle.Alignment = HorizontalAlignment.Center;
                    IFont font = workbook.CreateFont();
                    font.FontHeightInPoints = 20;
                    font.Boldweight = 700;
                    headStyle.SetFont(font);

                    headerRow.GetCell(0).CellStyle = headStyle;
                    //sheet.AddMergedRegion(new Region(0, 0, 0, dtSource.Columns.Count - 1));
                    sheet.AddMergedRegion(new NPOI.SS.Util.CellRangeAddress(0, 0, 0, dtSource.Columns.Count - 1));
                }
                #endregion


                #region 列头及样式
                {
                    //HSSFRow headerRow = sheet.CreateRow(1);
                    IRow headerRow = sheet.CreateRow(1);

                    ICellStyle headStyle = workbook.CreateCellStyle();
                    headStyle.Alignment = HorizontalAlignment.Center;
                    IFont font = workbook.CreateFont();
                    font.FontHeightInPoints = 10;
                    font.Boldweight = 700;
                    headStyle.SetFont(font);

                    for (int i = 0; i < oldColumnNames.Length; i++)
                    {
                        headerRow.CreateCell(i).SetCellValue(newColumnNames[i]);
                        headerRow.GetCell(i).CellStyle = headStyle;
                        //设置列宽
                        sheet.SetColumnWidth(i, (arrColWidth[i] + 1) * 256);
                    }
                    /*
                    foreach (DataColumn column in dtSource.Columns)
                    {
                        headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                        headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                        //设置列宽   
                        sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);
                    }
                     * */
                }
                #endregion

                rowIndex = 2;
            }
            #endregion


            #region 填充内容
            IRow dataRow = sheet.CreateRow(rowIndex);
            //foreach (DataColumn column in dtSource.Columns)
            for (int i = 0; i < oldColumnNames.Length; i++)
            {
                ICell newCell = dataRow.CreateCell(i);

                string drValue = row[oldColumnNames[i]].ToString();

                switch (dtSource.Columns[oldColumnNames[i]].DataType.ToString())
                {
                    case "System.String"://字符串类型   
                        newCell.SetCellValue(drValue);
                        break;
                    case "System.DateTime"://日期类型   
                        DateTime dateV;
                        DateTime.TryParse(drValue, out dateV);
                        newCell.SetCellValue(dateV);

                        newCell.CellStyle = dateStyle;//格式化显示   
                        break;
                    case "System.Boolean"://布尔型   
                        bool boolV = false;
                        bool.TryParse(drValue, out boolV);
                        newCell.SetCellValue(boolV);
                        break;
                    case "System.Int16"://整型   
                    case "System.Int32":
                    case "System.Int64":
                    case "System.Byte":
                        int intV = 0;
                        int.TryParse(drValue, out intV);
                        newCell.SetCellValue(intV);
                        break;
                    case "System.Decimal"://浮点型   
                    case "System.Double":
                        double doubV = 0;
                        double.TryParse(drValue, out doubV);
                        newCell.SetCellValue(doubV);
                        break;
                    case "System.DBNull"://空值处理   
                        newCell.SetCellValue("");
                        break;
                    default:
                        newCell.SetCellValue("");
                        break;
                }

            }
            #endregion

            rowIndex++;
        }


        using (MemoryStream ms = new MemoryStream())
        {
            workbook.Write(ms);
            ms.Flush();
            ms.Position = 0;

            //sheet.Dispose();
            sheet = null;
            workbook = null;
            //workbook.Dispose();//一般只用写这一个就OK了，他会遍历并释放所有资源，但当前版本有问题所以只释放sheet   
            return ms;
        }
    }


    /// <summary>   
    /// WEB导出DataTable到Excel   
    /// </summary>   
    /// <param name="dtSource">源DataTable</param>   
    /// <param name="strHeaderText">表头文本</param>   
    /// <param name="strFileName">文件名</param>   
    /// <Author>chenjh 2010-5-8 22:21:41</Author>   
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName)
    {
        ExportByWeb(dtSource, strHeaderText, strFileName, "sheet");
    }

    /// <summary>
    /// WEB导出DataTable到Excel
    /// </summary>
    /// <param name="dtSource">源DataTable</param>
    /// <param name="strHeaderText">表头文本</param>
    /// <param name="strFileName">输出文件名，包含扩展名</param>
    /// <param name="oldColumnNames">要导出的DataTable列数组</param>
    /// <param name="newColumnNames">导出后的对应列名</param>
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName, string[] oldColumnNames, string[] newColumnNames)
    {
        ExportByWeb(dtSource, strHeaderText, strFileName, "sheet", oldColumnNames, newColumnNames);
    }

    /// <summary>
    /// WEB导出DataTable到Excel
    /// </summary>
    /// <param name="dtSource">源DataTable</param>
    /// <param name="strHeaderText">表头文本</param>
    /// <param name="strFileName">输出文件名</param>
    /// <param name="strSheetName">工作表名称</param>
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName, string strSheetName)
    {
        HttpContext curContext = HttpContext.Current;

        // 设置编码和附件格式   
        curContext.Response.ContentType = "application/vnd.ms-excel";
        curContext.Response.ContentEncoding = Encoding.UTF8;
        curContext.Response.Charset = "";
        curContext.Response.AppendHeader("Content-Disposition",
            "attachment;filename=" + HttpUtility.UrlEncode(strFileName, Encoding.UTF8));

        //生成列
        string columns = "";
        for (int i = 0; i < dtSource.Columns.Count; i++)
        {
            if (i > 0)
            {
                columns += ",";
            }
            columns += dtSource.Columns[i].ColumnName;
        }

        curContext.Response.BinaryWrite(Export(dtSource, strHeaderText, strSheetName, columns.Split(','), columns.Split(',')).GetBuffer());
        curContext.Response.End();

    }

    /// <summary>
    /// 导出DataTable到Excel
    /// </summary>
    /// <param name="dtSource">要导出的DataTable</param>
    /// <param name="strHeaderText">标题文字</param>
    /// <param name="strFileName">文件名，包含扩展名</param>
    /// <param name="strSheetName">工作表名</param>
    /// <param name="oldColumnNames">要导出的DataTable列数组</param>
    /// <param name="newColumnNames">导出后的对应列名</param>
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName, string strSheetName, string[] oldColumnNames, string[] newColumnNames)
    {
        HttpContext curContext = HttpContext.Current;

        // 设置编码和附件格式   
        curContext.Response.ContentType = "application/vnd.ms-excel";
        curContext.Response.ContentEncoding = Encoding.UTF8;
        curContext.Response.Charset = "";
        curContext.Response.AppendHeader("Content-Disposition",
            "attachment;filename=" + HttpUtility.UrlEncode(strFileName, Encoding.UTF8));

        curContext.Response.BinaryWrite(Export(dtSource, strHeaderText, strSheetName, oldColumnNames, newColumnNames).GetBuffer());
        curContext.Response.End();
    }

    /// <summary>读取excel   
    /// 默认第一行为表头，导入第一个工作表
    /// </summary>   
    /// <param name="strFileName">excel文档路径</param>   
    /// <returns></returns>   
    public static DataTable Import(string strFileName)
    {
        DataTable dt = new DataTable();

        HSSFWorkbook hssfworkbook;
        using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
        {
            hssfworkbook = new HSSFWorkbook(file);
        }
        ISheet sheet = hssfworkbook.GetSheetAt(0);
        System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

        IRow headerRow = sheet.GetRow(0);
        int cellCount = headerRow.LastCellNum;

        for (int j = 0; j < cellCount; j++)
        {
            ICell cell = headerRow.GetCell(j);
            dt.Columns.Add(cell.ToString());
        }

        for (int i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++)
        {
            IRow row = sheet.GetRow(i);
            DataRow dataRow = dt.NewRow();

            for (int j = row.FirstCellNum; j < cellCount; j++)
            {
                if (row.GetCell(j) != null)
                    dataRow[j] = row.GetCell(j).ToString();
            }
            dt.Rows.Add(dataRow);
        }
        return dt;
    }
    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="strFileName">Excel文件全路径(服务器路径)</param>
    /// <param name="SheetName">要获取数据的工作表名称</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(string strFileName, string SheetName, int HeaderRowIndex)
    {
        using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
        {
            IWorkbook workbook = new HSSFWorkbook(file);
            return RenderDataTableFromExcel(workbook, SheetName, HeaderRowIndex);
        }
    }

    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="strFileName">Excel文件全路径(服务器路径)</param>
    /// <param name="SheetIndex">要获取数据的工作表序号(从0开始)</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(string strFileName, int SheetIndex, int HeaderRowIndex)
    {
        using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
        {
            IWorkbook workbook = new HSSFWorkbook(file);
            string SheetName = workbook.GetSheetName(SheetIndex);
            return RenderDataTableFromExcel(workbook, SheetName, HeaderRowIndex);
        }
    }

    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="ExcelFileStream">Excel文件流</param>
    /// <param name="SheetName">要获取数据的工作表名称</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(Stream ExcelFileStream, string SheetName, int HeaderRowIndex)
    {
        IWorkbook workbook = new HSSFWorkbook(ExcelFileStream);
        ExcelFileStream.Close();
        return RenderDataTableFromExcel(workbook, SheetName, HeaderRowIndex);
    }

    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="ExcelFileStream">Excel文件流</param>
    /// <param name="SheetIndex">要获取数据的工作表序号(从0开始)</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(Stream ExcelFileStream, int SheetIndex, int HeaderRowIndex)
    {
        IWorkbook workbook = new HSSFWorkbook(ExcelFileStream);
        ExcelFileStream.Close();
        string SheetName = workbook.GetSheetName(SheetIndex);
        return RenderDataTableFromExcel(workbook, SheetName, HeaderRowIndex);
    }

    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="workbook">要处理的工作薄</param>
    /// <param name="SheetName">要获取数据的工作表名称</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(IWorkbook workbook, string SheetName, int HeaderRowIndex)
    {
        ISheet sheet = workbook.GetSheet(SheetName);
        DataTable table = new DataTable();
        try
        {
            IRow headerRow = sheet.GetRow(HeaderRowIndex);
            int cellCount = headerRow.LastCellNum;

            for (int i = headerRow.FirstCellNum; i < cellCount; i++)
            {
                DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
                table.Columns.Add(column);
            }

            int rowCount = sheet.LastRowNum;

            #region 循环各行各列,写入数据到DataTable
            for (int i = (sheet.FirstRowNum + 1); i < sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);
                DataRow dataRow = table.NewRow();
                for (int j = row.FirstCellNum; j < cellCount; j++)
                {
                    ICell cell = row.GetCell(j);
                    if (cell == null)
                    {
                        dataRow[j] = null;
                    }
                    else
                    {
                        //dataRow[j] = cell.ToString();
                        switch (cell.CellType)
                        {
                            case CellType.Blank:
                                dataRow[j] = null;
                                break;
                            case CellType.Boolean:
                                dataRow[j] = cell.BooleanCellValue;
                                break;
                            case CellType.Numeric:
                                dataRow[j] = cell.ToString();
                                break;
                            case CellType.String:
                                dataRow[j] = cell.StringCellValue;
                                break;
                            case CellType.Error:
                                dataRow[j] = cell.ErrorCellValue;
                                break;
                            case CellType.Formula:
                            default:
                                dataRow[j] = "=" + cell.CellFormula;
                                break;
                        }
                    }
                }
                table.Rows.Add(dataRow);
                //dataRow[j] = row.GetCell(j).ToString();
            }
            #endregion
        }
        catch (System.Exception ex)
        {
            table.Clear();
            table.Columns.Clear();
            table.Columns.Add("出错了");
            DataRow dr = table.NewRow();
            dr[0] = ex.Message;
            table.Rows.Add(dr);
            return table;
        }
        finally
        {
            //sheet.Dispose();
            workbook = null;
            sheet = null;
        }
        #region 清除最后的空行
        for (int i = table.Rows.Count - 1; i > 0; i--)
        {
            bool isnull = true;
            for (int j = 0; j < table.Columns.Count; j++)
            {
                if (table.Rows[i][j] != null)
                {
                    if (table.Rows[i][j].ToString() != "")
                    {
                        isnull = false;
                        break;
                    }
                }
            }
            if (isnull)
            {
                table.Rows[i].Delete();
            }
        }
        #endregion
        return table;
    }
}